protocol: switch to single-funder anchor model.

Most complex change was gather_updates(), which handles all the "what
is the current state of the channel" logic for our dumb test utils.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

test-cli/gather_updates.h

@@ -0,0 +1,16 @@
+#ifndef GATHER_UPDATES_H
+#define GATHER_UPDATES_H
+#include "lightning.pb-c.h"
+
+struct signature;
+struct sha256;
+
+uint64_t gather_updates(const OpenChannel *o1, const OpenChannel *o2,
+			const OpenAnchor *oa,
+			char **argv,
+			uint64_t *our_amount, uint64_t *their_amount,
+			struct sha256 *our_rhash,
+			struct sha256 *their_rhash,
+			struct signature *their_commit_sig);
+
+#endif /* GATHER_UPDATES_H */